Method for increasing hydrophilicity of transparencies used as recording media in a thermal ink jet printer

- Xerox Corporation

A transparency for ink jet printing is enhanced for use as an ink jet recording medium by increasing the hydrophilicity of the coating formed on a transparent substrate. In one embodiment, the coating is subjected to a corona plasma discharge exposure to create changes in oxygen functionality at the coating surface resulting in increases in surface hydrophilicity. In another embodiment, the surface is exposed with UV radiation and ozone exposure for controlled periods of time. In both cases, the surface hydrophilicity is increased by generating highly reactive free radical oxygen (O.sup.-) which results primarily in increases in the oxygen functional groups C.dbd.O and COO.sup.-.

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Claims

1. A method for increasing the hydrophilicity of an ink recording media which comprises a transparent substrate upon which is formed a transparent coating comprising a plasticizer and a member selected from the group consisting of cellulose ester, alkyl cellulose, cyanoalkyl cellulose, carboxyalkyl cellulose, carboxyalkyl hydroxyalkyl cellulose, hydroxyalkyl cellulose, hydroxyalkyl methyl cellulose, acrylamide, a poly(alkylene oxide), and mixtures thereof comprising the steps of:

exposing a surface of the coating to a coronal discharge and
maintaining the discharge for a time sufficient to create oxygen functionality changes at the surface of the coating.

2. The method of claim 1 wherein said oxygen functionality changes generate highly reactive free radical oxygen (O.sup.-) resulting in increases in C.dbd.O and COO.sup.-.

3. The method of claim 1 further including the further steps of first projecting ink droplets onto the unexposed coating and measuring spot diameter of the projected droplets and the additional step of projecting ink droplets onto the exposed coating surface and measuring the spot diameter of the projected droplet and

adjusting the exposure for a period of time to increase spot diameter size 15% to 37% relative to the first measured diameter size.

4. The method of claim 1 wherein said transparent substrate is selected from the group consisting of poly(ethylene terephthalate), cellulose acetate, cellophane, polysulfone, polyvinyl chloride, and polypropylene.

5. A method for forming a transparency for use as an ink jet recording sheet comprising the steps of:

forming a supporting substrate selected from the group consisting of poly(ethylene terephthalate), cellulose acetate, cellophane, polysulfone, polyvinyl chloride, and polypropylene,
forming a coating on said substrate, the coating comprising a plasticizer and a member selected from the group consisting of cellulose ester, alkyl cellulose, cyanoalkyl cellulose, carboxyalkyl cellulose, carboxyalkyl hydroxyalkyl cellulose, hydroxyalkyl cellulose, hydroxyalkyl methyl cellulose, acrylamide, a poly(alkylene oxide), and mixtures thereof and
exposing a surface of the coating to UV radiation and ozone simultaneously over a predetermined time sufficient to cause changes in the oxygen functionality at the surface to a depth of about one micron.

6. The method of claim 5 wherein said oxygen functionality changes result in generation of highly reactive free radical oxygen (O--) which results in increases in C.dbd.O and COO--.

Referenced Cited
U.S. Patent Documents
3846141 November 1974 Ostergren et al.
4638377 January 20, 1987 Dakin
4673627 June 16, 1987 Kunichika et al.
4725862 February 16, 1988 Matsuzaki
4865914 September 12, 1989 Malhotra
4877688 October 31, 1989 Senoo et al.
5006407 April 9, 1991 Malhotra
5100469 March 31, 1992 Pontes et al.
5141556 August 25, 1992 Matrick
5229172 July 20, 1993 Cahalan et al.
5372884 December 13, 1994 Abe et al.
Other references
  • Dr. N. Stewart McIntyre and Mary Jane Walzak, "New UV/Ozone Treatment Improves Adhesiveness of Polymer Surfaces," Modern Plastics, Mar. 1996, pp. 79-81.
Patent History
Patent number: 5780118
Type: Grant
Filed: Jul 1, 1996
Date of Patent: Jul 14, 1998
Assignee: Xerox Corporation (Stamford, CT)
Inventors: Mark D. Tracy (Rochester, NY), Dale R. Ims (Webster, NY)
Primary Examiner: Bernard Pianalto
Application Number: 8/673,533